Sparking plug for internal combustion engines



' y 1935- G. E. WQODS HUMPHERY ET AL 2,008,298

7 SPARKING PLUG FOR INTERNAL COMBUSTION ENGINES m Jan. 4, 1954 Fig. 1.

Patented July 16, 1935 .PATENT OFFICE SPARKING PLUG FOR INTERNAL COMBUSTION ENGINES George EdwardWoods-Humphery, Chelsea, Lon- London, England don, and Henry Leonard Hall, Streatham,

- Application'Januai-y 4, 1934, Serial No. "705,246

' In Great Britain January 6, 1933 Claims. (01. 123-469) This invention relates to sparking plugs for internal combustion engines and has for its object the provsion of means which will enable the plug without alteration to be equally, suitable for use 5 in very hot or very oily engines.

Hitherto it has beenheld that characteristically different types of plugs are essential for eflicient operation in hot and oily engines respectively, and because of this widely accepted theory, manufacturers of sparking plugs offer and recommend for use in hot engines plugs which diiler very considerably in construction from those they oifer for use in oily engines. a

It is proposed. to attain the object of this invention and to overcome the disadvantages of the present plugs bythe combination with said plugs of means, interposed between and formed separately from the engine cylinder, which means will prevent said plugs from reaching unduly high temperatures and trap ,oil and other foreign matterwhich maybe suspended in the combustible gases which are caused to pass through a labyrinth before reaching the igniter chamber in which the sparking points are located. s

Inthe accompanying drawing which illustrates this inventiom- 7 Figure. l is a longitudinal elevation,-partly in section, of ,a'sparking plug with an igniter protector constructed in accordance with one embodiment of this invention, and, Figures 2, 3 and 4 aresimilar views illustrating three further embodiments;

Referring to Figure 1, the igniter protector comprises a hollow-cylindrical internally screw threaded body part' I furnished at one end with anuexternally screw threaded chambered extension 2 ofreduced diameter adapted to besecured in the engine cylinder in place of the usual sparking plug. The part I of the-igniter'is adapted to 40 receive (a) a baflle 3, part of which is adapted to enter the extension 2 so as'to form a chamber 4 and (b) the screw threaded end of a sparking plug 5 of any suitable type. The outer end of the extension 2 and the end wall of the chamber 4 45 are formed conical as shown and said extension is further provided with a centrally and axially disposed aperture 6 opening into the chamber 4. The bafiie 3 is furnished with a conical depression 1 and with a plurality of longitudinally disposed passages 8 adapted to place the chamber 4 in communication with an igniter chamber 9 formed between the end of the sparking plug 5 and the inner end of bafiie 3. The aperture 6, chamber.

4 and passages 8 combine to form a labyrinth or other foreign matter reaching the igniterchamber 9.

In operation the combustible mixture within the engine; cylinder passes through the aperture 6 and into the conical depression 1 which deflects it onto the walls of the chamber 4 on which are 7 other foreign matter and it will also be seen that the small and tortuous passages in the labyrinth greatly reduce the intensity of the attack of the burning gases on the sparking points of the plug 5 and also that this provision for keeping the firsing points of the sparking plug at a reasonably lowtemperature is aided by placing the firing points as remote from the engine cylinder as is desirable and'also by providing relatively heavy masses of metal which ensure good heat-flow from the baffle 3 to the body I and thereby to the atmosphere and also from said body through extension '2 to the body of the engine cylinder.

When the piston of the engine is at the end of the induction stroke the interior'of the igniter protector contains a quantity of burnt gas which, on the compression stroke, is compressed into the space behind the firing points and forms a cushion of inert gas which minimizes the attack of the burning gases on the adjacent surfaces of the sparking plug; it will be apparent that the quantityof burntgas trapped in this way must be adjusted to ensure the presence of combustible mixture at the firing points and in the labyrinth.

@It follows that this-combination of provisions results in a sparking plug which will keep suinciently cool in a hot engine and will also have great resistance to oiling up in any engine.

In the modification illustrated in Figure 2, the bafile 3 is formed integrally with the body I, and the labyrinth is formed by the axial passage 6, radial passages l0, annular chamber ll provided around the extension 2 and angular passages [2 which open into the igniter chamber 9.

In the modification illustrated in Figure 3, the battle 3 is formed integrally with the extension 2 and isprovided with the conical depression I and angularly disposed passages I3 opening into the igniter chamber 9. The end M of the extension 2 is in this case formed separately and is secured in position in any convenient manner, such as by spinning over the upper edge 15 of the top of the extension 2. In this construction the sparking plug comprises a screw threaded part [6 and a central electrode ll, the outer or negative points l8 which coact with the electrode l'l being provided on the bafile 3.

The modifications illustrated in Figure 4 is simi lar to Figure 3, but in this case the baffle 3 carrying the negative points I8, is formed separately from the extension 2 and is secured therein in any convenient manner and the conical end I4 is formed integrally with the extension 2.

The operation of the devices illustrated in Figures 2, 3 and 4 is the same as that described in connection with Figure l and further description is therefore unnecessary.

What we claim is:-

l 1. An ignition device for use in internal combustion engines, comprising in combination, an igniter unit, and an igniter protector comprising a body portion in which the igniter unit is screwed, a screw threaded extension adapted to be screwed into the engine cylinder, an axially disposed aperture in the end of said extension, abaflie within said extension, a chamber between one face of said baffle and the inner wall of said axially disposed aperture, a conical recess in that end of the 'baflie forming the opposite'wall of said chamber,

an igniter chamber formed between the end of the igniter unit and the other face of said bafile and a plurality of passages in said baffle arranged out of alignment with said axially disposed aperture constituting a labyrinth connecting the first named chamber with the igniterchamb'er.

2. In an ignition device for use in internal combustion engines thecombination of an igniter unit comprising a sparking plug and an igniter protector comprising an internally screw threaded body portion in which the sparking plug is screwed, an externally screw threaded extension on said igniter protector adapted to be screwed into the engine cylinder, an axially disposed aperture in the end of said extension, a partially screw threaded bafile screwed'into said body pore tion, a conical recess in one end of said bailie, a

chamber formed between one face of said baiiie and the inner wall of said axially disposed aperture, an igniter chamber formed between the other face of said battle and the end of the sparking plug, and, a plurality of passages in said baille arranged out of alignment with the axially disposed aperture in the end of the extension con,- stituting with said aperture and the first named chamber a labyrinth leading to the igniter chamber. 3. In an ignition device for use in internal combustion engines, the combination of an igniter unit comprising a sparking plug and an igniter protector comprising an internally screw threaded body portion in which the sparking plug is screwed, an externally screw threaded extension on said igniter protector adapted to be screwed into the engine cylinder, a baflie within and formed integrally with said extension, an igniter chamber on one side of said baflle, an axially disposed aperture in the end of said extension on the other side of said baffle, an annular chamber around said extension, a plurality of radially disposed passages in said extension adjacent said baflie and communicating with said annular chamber and a plurality of angularly disposed passages in said baffle connecting said annular chamber with'the igniter chamber.

4. In an igniter device for use in internal combustion engines, the combination of an igniter unit comprising an externally screw threaded body and a centrally disposed electrode secured therein and an igniter protector comprising an internally screw threaded body portion in which the externallyscrew threaded body of the igniter unit is screwed, an externally screw threaded extension on said igniter protector adapted to be screwed into the engine cylinder, a baffle within and formed integrally with said extension, a plurality of sparking points on one side of said b-afiie arranged to co-operate with the centrally disposed electrode, an igniter chamber in which said sparking points and electrode are located, a conical recess formed in the opposite side of said baiiie, a conical end piece fitted to the end of said extension, an axially disposed aperture in said end piece, a chamber, the end walls of which are formed by the conical recess in the baflle and the inner wall of the conical end piece and a plurality of passages in said bafile connecting the last unit comprising an externally screw threaded body and a centrally disposed electrode secured therein, and an igniter protector comprising an internally screw threaded body portion in which the externally screw threaded bodyof the igniter unit is screwed, an externally screw threaded extension on said igniter protector adapted to be screwed into the engine cylinder, an axially disposed aperture in the end of said extension, a baflie within and formed separately from said extension, a plurality of sparking points on one side of said bafile arranged to co-operate with the centrally disposed electrode, an igniter chamber in which said sparking points and electrode are located, a conical recess formed in the opposite side of said baflle, a chamber between the side of said baflie last named and the inner end wall of the extension and a plurality of passages in said baflieconnecting the last named chamber with the igniter chamber.

GEORGE EDWARD WOODS-HUMPHERY. HENRY LEONARD HALL. r r 

